rr = RunRyder.com. 3 people at the same time? We don't have one here in europe in a year?!?

To get things sorted: What interface? Stick or cable interface?
Make sure the wiring is like that:
Make sure, your MPX software has assigned inputs (gimbals/pots) to functions and functions to channels.
Make sure, the MPX software has STUDNET enabled and TEACHER disabled.

IF you have the cable interface and use an adapter from the 3.5 mm to 5-pin DIN, make sure the mono or stereo jack corresponds to the socket in the adapter.

Anyway, the Reflex guys are in Los Angeles next week for IHobby show. Just grab your stuff and get it sorted locally. Could be funny.